This disclosure relates generally to check valves. More specifically, this disclosure relates to check valves for a high-volume low-pressure (“HVLP”) spray system.
HVLP spray systems produce a high volume of air flow at low pressures to apply a spray of fluid, such as paint, water, oil, stains, finishes, coatings, solvents, and solutions, among others, to a surface. A compressor typically drives compressed air to a spray gun to generate the spray of fluid. The high volume and low pressure of the compressed air provided to the spray gun can cause check valves between the compressor and the spray gun to behave in an unstable manner. For example, the check valve can be pressure-activated based on a pressure differential between a downstream (closer to the spray gun) pressure and an upstream (closer to the compressor) pressure. When the user activates the spray gun, the downstream pressure can drop rapidly causing the check valve to open, but the compressor can quickly equalize the pressure, causing the check valve to close. The check valve closing leads to a rapid drop in downstream pressure, again causing the check valve to open. The rapid opening and closing of the check valve can cause chattering within the check valve, which can lead to excessive noise, wear, and an oscillating air supply.